BANGKOK —
Opposition lawmakers in Cambodia boycotted the opening of a new session of parliament on Monday because authorities have refused to hold an independent inquiry into alleged vote-rigging by the party of long-serving Prime Minister Hun Sen.

Security at the National Assembly and elsewhere in Phnom Penh was tight, with many roads blocked off.

“Our goal still stands. We are boycotting today's meeting because the truth has not been uncovered and there has been no breakthrough,” Yim Sovann, a lawmaker for the opposition Cambodia National Rescue Party (CNRP) told Reuters.

“This meeting is a violation of the constitution,” he said.

The National Election Committee (NEC) says Hun Sen's Cambodian People's Party (CPP) won 68 seats in the July 28 election to the CNRP's 55. The CNRP says it was cheated out of 2.3 million votes that would have handed it victory.

The opposition and some political analysts say a quorum of 120 lawmakers is needed to open parliament. Hun Sen has ignored that, saying the rules stipulate a new government can be appointed with 63 of the 123 lawmakers voting in favor.

Last week, King Norodom Sihamoni turned down a request from the CNRP to delay the start of parliament, saying he was constitutionally required to preside over the opening within 60 days of the poll.

In an address to the house on Monday, the king congratulated the newly elected members of parliament and said they had to put the nation's interest before anything else.

“The Cambodian nation must stand united and show the highest national solidarity based on the implementation of the principles of democracy and rule of law that we have been practicing since 1993,” he said.

That year Cambodia held its first elections, under United Nations supervision, since the ultra-Maoist Khmer Rouge regime of the late 1970s and the civil war that followed.

King Sihamoni took the throne in 2004 after the abdication of his father Sihanouk, who was given a lavish state burial after his death last year. King Sihamoni does not enjoy his father's semi-divine status among Cambodians.

Hun Sen, 61, has been in power for 28 years and has said he would rule Cambodia into his seventies.

He portrays himself as the man who saved Cambodia from the terror and chaos of the Khmer Rouge years, but his authoritarian rule, along with widespread corruption, alienated many young people who did not live through that era and who turned to the newly merged opposition CNRP in the election.